"Astrology works" is a scientific theory to the degree that it is, in fact, acceptable science to do an experiment to see whether or not astrology has predictive power. It's rhetorically inaccurate to say that means "astrology is science" though, because of course the practice of astrology is not. But sure, it's probably a good idea to include other conditions. Excessively unlikely (or non-reductionist?) hypotheses could be classified as non-scientific, for the simple reason that even considering them in the first place would be a case of privileging the hypothesis.

None of this contradicts falsifiability being "a way of distinguishing scientific theories about the world from other theories about the world", if we have other ways of distinguishing scientific from non-scientific, such as "reductionism".